The 25-year-old is deemed surplus to requirements at Manchester United and is poised to rejoin the club where he won two Bundesliga titles in as many seasons.
Borussia Dortmund will seal a deal worth up to 12.5 million euros for Manchester United misfit Shinji Kagawa within the next 48 hours.
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On Thursday Goal reported that Dortmund was in talks to re-sign Kagawa, who has failed to establish himself at Old Trafford since moving from Signal Iduna Park for around €20 million back in June 2012.
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Now BVB has agreed a deal worth an initial €7.5 million with up to €5 million in add-ons for the Japan international, who will sign a four-year contract to rejoin his former club.
Confirming talks with United about Kagawa on Friday, Dortmund's youth coordinator Lars Ricken told Sky Sport Germany: "We still have two or three days left [of the transfer window]. Then we will see if he wears the Dortmund jersey again."
Kagawa remains a popular figure at Dortmund, where he won two Bundesliga titles and a DFB-Pokal in his two seasons at the club after joining for €350,000 from J-League club Cerezo Osaka in 2010.
Van Gaal considers the 25-year-old surplus to his requirements at Old Trafford, having already spent over €150 million to recruit Luke Shaw, Ander Herrera and Angel Di Maria this summer.
United will also make a final push to sign Juventus midfielder Arturo Vidal and Ajax star Daley Blind before the transfer window slams shut on Monday.